Disable Media/File Caching

[iainbrighton]

Related to discussions in issue #9, it would be great to be able the disabling of file-based media, i.e. ISO and WIM media. This would be good for reducing disk storage on always-connected hosts, e.g. not laptops! By default this should be left enabled for performance reasons.

[iainbrighton]

It appears that mounting an ISO file from a UNC file share doesn't work too well? When an ISO is mounted with Mount-DiskImage -ImagePath '\\UNC\Path\To.Iso' -StorageType ISO -PassThru, it is not reflected in any subsequent calls to Get-Volume?

DriveLetter FileSystemLabel           FileSystem DriveType HealthStatus OperationalStatus
----------- ---------------           ---------- --------- ------------ -----------------
F                                                CD-ROM    Healthy      Unknown
C           Evo850                    NTFS       Fixed     Healthy      OK
D           Data                      NTFS       Fixed     Healthy      OK
            Recovery                  NTFS       Fixed     Healthy      OK
                                      NTFS       Fixed     Healthy      OK
E           M4                        NTFS       Fixed     Healthy      OK

When -ImagePath points to a local path Get-Volume shows this:

DriveLetter FileSystemLabel           FileSystem DriveType HealthStatus OperationalStatus
----------- ---------------           ---------- --------- ------------ -----------------
F                                                CD-ROM    Healthy      Unknown
C           Evo850                    NTFS       Fixed     Healthy      OK
D           Data                      NTFS       Fixed     Healthy      OK
            Recovery                  NTFS       Fixed     Healthy      OK
                                      NTFS       Fixed     Healthy      OK
R           IR3_SSS_X64FREE_EN-US_DV9 UDF        CD-ROM    Healthy      OK
E           M4                        NTFS       Fixed     Healthy      OK

In short, to progress this, I need a way of determining the mounted drive letter of an ISO mounted on a UNC share. Get-CimInstance -ClassName Win32_Volume and Get-WmiObject -Class Win32_Volume return the mounted ISO, but I cannot work out how to get back to the source file path..

[iainbrighton]

Creating a Windows Image from a networked .WIM files does work (as I expected).

I think I'll temporarily only implement the -DisableLocalFileCaching functionality for .WIM media. ISO media will still be downloaded/cached locally until I can get to the bottom of the ISO mounting issue described above.

[iainbrighton]

@csandfeld If you have some WIM files you should be able to run Set-LabHostDefaults -DisableLocalFileCaching to stop the module copying .WIM files from an existing location (as long as the Uri starts with file://). This is implemented in v0.8.6

Note: this is only currently implemented for WIM media.

[csandfeld]

All my wishes seem to come true today :)

[iainbrighton]

Haha – not quite. There’s one more inbound…

[csandfeld]

Tried disabling file caching for a WIM file, but ran into the following:

VERBOSE: [13:25:07] Caching of file-based media is disabled. Skipping media 'S12R2STDX64' download.
Get-Item : Cannot find path 'D:\TestLab\ISOs\S12R2STDX64.wim' because it does not exist.
At C:\Program Files\WindowsPowerShell\Modules\VirtualEngineLab\Src\LabMedia.ps1:240 char:17
+ ...     return (Get-Item -Path $invokeResourceDownloadParams.DestinationP ...
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (D:\TestLab\ISOs\S12R2STDX64.wim:String) [Get-Item], ItemNot 
   FoundException
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.GetItemCommand

VERBOSE: [13:25:07] Creating disk image 'Windows Server 2012 R2 Standard x64'.
VERBOSE: [13:25:07] Creating disk image 'D:\TestLab\MasterVirtualHardDisks\S12R2STDX64.vhdx'.
VERBOSE: [13:25:08] Mounting disk image 'D:\TestLab\MasterVirtualHardDisks\S12R2STDX64.vhdx'.
VERBOSE: [13:25:08] Initializing disk image 'D:\TestLab\MasterVirtualHardDisks\S12R2STDX64.vhdx'.
VERBOSE: [13:25:09] Creating 'System' disk partition.
VERBOSE: [13:25:09] Formatting 'System' disk partition.
VERBOSE: [13:25:10] Creating 'OS' disk partition.
VERBOSE: [13:25:10] Formatting 'OS' disk partition.
New-LabImage : Cannot bind argument to parameter 'MediaPath' because it is an empty string.
At C:\Program Files\WindowsPowerShell\Modules\VirtualEngineLab\Src\LabVM.ps1:211 char:27
+ ... ef] $null = New-LabImage -Id $node.Media -ConfigurationData $Configur ...
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,New-LabImage

WARNING: [13:25:13] Removing incomplete image 'D:\TestLab\MasterVirtualHardDisks\S12R2STDX64.vhdx'.
VERBOSE: [13:25:13] Setting Virtual Switch configuration 'External'.
VERBOSE: [13:25:13] Checking DSC Resource 'xHyper-V\MSFT_xVMSwitch'.
VERBOSE: [13:25:13] Invoking command 'Test-VMSwitchTargetResource'.
VERBOSE: [13:25:15] Skipping command 'Set-VMSwitchTargetResource'.
VERBOSE: [13:25:15] (Re)setting VHDX configuration 'S12R2STDX64'.
VERBOSE: [13:25:15] Checking DSC Resource 'xHyper-V\MSFT_xVHD'.
VERBOSE: [13:25:15] Invoking command 'Test-VHDTargetResource'.
Either specify ParentPath or MaximumSize property.
At C:\Program Files\WindowsPowerShell\Modules\VirtualEngineLab\DSCResources\xHyper-V\DSCResources\MSFT_xVHD
\MSFT_xVHD.psm1:199 char:8
+        Throw "Either specify ParentPath or MaximumSize property."
+        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OperationStopped: (Either specify ...mSize property.:String) [], RuntimeExce 
   ption
    + FullyQualifiedErrorId : Either specify ParentPath or MaximumSize property.


C:\> 

[iainbrighton]

OK – I think I can see what the issue is there. I best be writing another test ;)

[iainbrighton]

@csandfeld this should be resolved in the latest dev branch 0.8.9. I've merged the -Credential/-Password functionality into dev.

[csandfeld]

That did the trick - you're a rock star 👍

[iainbrighton]

@csandfeld can I close this issue out?

[csandfeld]

Yes, certainly - thank you